Wet processing apparatus and plating apparatus

ABSTRACT

A wet processing apparatus, such as a plating apparatus, and an etching apparatus, is disclosed. A wet processing apparatus includes a substrate-holder advancing mechanism configured to elevate a movable support to raise a substrate holder until the substrate holder is separated from a fixed support, move the movable support together with the substrate holder by a predetermined distance toward a holder takeout position, lower the movable support until the substrate holder is supported on the fixed support and the movable support is separated from the substrate holder, and move the movable support by the predetermined distance toward a holder put-in position.

CROSS REFERENCE TO RELATED APPLICATIONS

This document claims priorities to Japanese Patent Application No. 2013-144239 filed Jul. 10, 2013 and Japanese Patent Application No, 201456714 filed Mar. 19, 2014, the entire contents of which are hereby incorporated by reference.

BACKGROUND

An electroless plating apparatus is known which performs plating of a substrate, such as a wafer, by immersing the substrate in a plating solution in a plating bath. As shown in FIG. 8, in such an electroless plating apparatus, a number of substrate holders 101, each holding a substrate W, are suspended in a plating bath 100, and the substrates W are immersed in a plating solution. While the substrate holders 101 are moved horizontally in the plating bath 100, a metal film is deposited on the surface of each substrate W. After a predetermined processing time has elapsed since the substrates W were immersed in the plating solution held in the plating bath 100, the substrates W are raised from the plating bath 100.

In a plating process that entails a long processing time, it is common practice to arrange the substrates W with a narrow spacing therebetween in the plating bath 100 in order to increase a throughput so that a large number of the substrates W are immersed in the plating solution. The narrow spacing between the substrates W, however, has the following drawback. When the substrates W are moved horizontally, a plating solution existing between adjacent substrates W moves together with the substrates W, and thus is not likely to be replaced with a new plating solution. This will lead to insufficient supply of metal ions to the surface of each of the substrates W, resulting in a failure to form a metal film having a uniform thickness on the substrate of each substrate W.

In electroless plating of a substrate W, as the plating reaction progresses, a gas, such as hydrogen gas, is produced as a reaction by-product. The gas does not all rise to a surface of the plating solution, and the gas partly remains as bubbles on the surface of the substrate W. The gas bubbles remaining on the substrate W can interfere with uniform deposition of a metal film on the surface of the substrate W. It is therefore necessary to remove the gas bubbles from the surface of the substrate W.

Electroless plating is a technique to form a metal film on a target surface of a substrate by chemically reducing metal ions in a plating solution without passing an electric current through the plating solution. Such electroless plating is widely used in nickel-phosphorus plating, nickel-boron plating, copper plating for a printed circuit board, etc. in particular, electroless plating finds applications in wire bonding and formation of a metal layer, such as Co (cobalt) or Ni (nickel), on a surface of a conductive pad for electrical connection with solder bumps (see e.g., Japanese laid-open patent publication No. 2001-267356).

Plating apparatuses can be classified roughly into a single-substrate processing type and a batch processing type. A known electroless plating apparatus of the single-substrate processing type performs processing of a substrate while rotating the substrate held in a horizontal position (see e.g., Japanese laid-open patent publication No. 2002-129344). Such an electroless plating apparatus, especially when it is used to form a metal layer on a conductive pad, may have a drawback of low throughput due to a long overall plating time. Plating apparatuses of the batch processing type, on the other hand, has the following problems: As substrates are becoming larger these days, a transport mechanism of a carrier that holds a batch of substrates is becoming larger, thus leading to an increased installation area of the plating apparatus.

As substrates become larger and plating apparatuses become larger in scale, it becomes difficult for an operator to reach components (e.g., a plating bath, a substrate cleaning machine, etc.) of a plating apparatus, and as a result it becomes difficult to perform maintenance work on the plating apparatus.

It has been conventionally proposed to provide a plurality of processing lines to perform plating of substrates in parallel so as to increase the throughput or enhance the versatility of a system (see e.g., Japanese laid-open patent publications No. 06-158395 and No. 2001-335995). This system, however, requires use of a larger-scale plating apparatus which entails difficult maintenance work,

SUMMARY OF THE INVENTION

It is therefore a first object to provide a wet processing apparatus which can achieve uniform processing of a substrate.

It is a second object to provide a plating apparatus which, while achieving a high throughput, allows an operator to easily reach components of the plating apparatus, thus facilitating maintenance work on the plating apparatus.

The below-described embodiments are directed to a wet processing apparatus for processing a substrate, such as a wafer, with a processing liquid, such as a plating solution or an etching liquid, and to a plating apparatus for plating a surface of a substrate, such as a wafer.

In an embodiment, there is provided a wet processing apparatus comprising: a substrate holder configured to hold a substrate; a processing bath configured to store a processing liquid therein; and a substrate-holder advancing mechanism configured to move the substrate holder from a holder put-in position to a holder takeout position in the processing bath while keeping the substrate, held by the substrate holder, immersed in the processing liquid, wherein the substrate-holder advancing mechanism includes a fixed support configured to support the substrate holder and suspend the substrate holder in the processing bath, a movable support disposed adjacent to the fixed support and configured to support the substrate holder, and an actuator configured to elevate the movable support to raise the substrate holder until the substrate holder is separated from the fixed support, move the movable support together with the substrate holder by a predetermined distance toward the holder takeout position, lower the movable support until the substrate holder is supported on the fixed support and the movable support is separated from the substrate holder, and move the movable support by the predetermined distance toward the holder put-in position.

In an embodiment, the actuator comprises a first actuator configured to elevate and lower the movable support, and a second actuator configured to horizontally move the movable support.

In an embodiment, the wet processing apparatus further comprises: a transporter configured to horizontally transport the substrate holder; and a lifter configured to vertically transport the substrate holder between the transporter and the substrate-holder advancing mechanism, the lifter being configured to lower the substrate holder to immerse the substrate, held by the substrate holder, in the processing liquid in the processing bath and raise the substrate holder from the processing bath.

In an embodiment, the substrate holder has outwardly-projecting portions, and the fixed support has a plurality of recesses into which the projecting portions of the substrate holder are to be fitted.

In an embodiment, the movable support has a plurality of recesses into which the projecting portions of the substrate holder are to be fitted.

In an embodiment, there is provided a plating apparatus for plating a substrate, comprising: a substrate holder configured to hold the substrate; and a plurality of plating sections arranged in parallel, wherein each of the plating sections includes a plurality of processing baths used for plating of the substrate, and a substrate-holder transporter configured to transport the substrate holder, holding the substrate, between the processing baths, and wherein a maintenance space is provided between the plating sections.

In an embodiment, the maintenance space extends parallel to the substrate-holder transporter.

In an embodiment, a piping space in which pipes for conveying processing liquids to the processing baths are housed is formed below the maintenance space.

In an embodiment, a utility fluid introduction port configured to supply a utility fluid, which is necessary for operation of the plating apparatus, to the plating sections is provided below the maintenance space.

In an embodiment, the plating apparatus further comprises: a substrate transfer section disposed adjacent to the maintenance space and configured to transfer the substrate to the substrate holder transporter.

In an embodiment, the substrate transfer section includes a spin-rinse-dryer configured to dry the substrate by rotating the substrate, and the spin-rinse-dryer is disposed adjacent to the maintenance space.

In an embodiment, the plating sections are electroless plating sections.

In an embodiment, the plating sections are electroplating sections.

According to the wet processing apparatus of the above-described embodiments, a substrate holder is moved from the holder put-in position to the holder takeout position in the processing bath, while a substrate, held by the substrate holder, is kept immersed in a processing liquid and is moved up and down repeatedly in the processing solution. Because the surface of the substrate moves relative to the processing liquid, replacement of the processing liquid in contact with the substrate is promoted and, in addition, bubbles adhering to the surface of the substrate can be removed. It therefore becomes possible to achieve uniform processing of the substrate.

The plating apparatus according to the above-described embodiments is provided with the maintenance space disposed between the plating sections. Therefore, an operator can easily access components of the plating apparatus and can easily perform maintenance work on the components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic plan view of an electroless plating apparatus according to one embodiment;

FIG. 2 is a diagram showing a substrate holder;

FIG. 3 is a diagram showing a holding arm of the substrate holder;

FIG. 4 is a perspective view of a first plating bath and a substrate-holder advancing mechanism;

FIG. 5 is a diagram illustrating the operation of the substrate-holder advancing mechanism;

FIG. 6A is a diagram showing a substrate holder before it is raised by first actuators;

FIG. 6B is a diagram showing the substrate holder after it is raised by the first actuators;

FIG. 7 is a perspective view of the first plating bath, the substrate-holder advancing mechanism, and lifters;

FIG. 8 is a perspective view of a plating bath for performing electroless plating of substrates;

FIG. 9 is a schematic plan view of an electroless plating apparatus according to another embodiment;

FIG. 10 is a diagram showing a substrate holder;

FIG. 11 is a diagram showing a holding arm of the substrate holder;

FIG. 12 is a diagram showing the electroless plating apparatus of FIG. 9 as viewed in a direction of arrow A;

FIG. 13 is a schematic cross-sectional view taken along line B-B of FIG. 9; and

FIG. 14 is a schematic plan view of an electroless plating apparatus according to yet another embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will now be described with reference to the drawings.

A wet processing apparatus is an apparatus for processing a substrate, such as a wafer, with use of a processing liquid, such as a plating solution or an etching liquid. An electroless plating apparatus and a wet etching apparatus are examples of the wet processing apparatus. An electroless plating apparatus is a plating apparatus for plating a substrate surface with metal without passing an electric current through a plating solution. A wet etching apparatus is an etching apparatus for etching away a photoresist coating on a substrate surface by immersing the substrate in a liquid, such as an organic solvent, or for removing a seed layer of e.g., copper from a substrate surface by immersing the substrate in an etching liquid comprising a mixture of sulfuric acid and hydrogen peroxide. The following description illustrates an electroless plating apparatus as one embodiment of the wet processing apparatus, although the wet processing apparatus is not limited to the electroless plating apparatus.

FIG. 1 is a schematic plan view of an electroless plating apparatus according to one embodiment. As shown in FIG. 1, the electroless plating apparatus includes a frame 1, loading ports 2 on which wafer cassettes, each housing substrates W (e.g., wafers) therein, are placed, a controller 3 for controlling operation of the electroless plating apparatus, and an aligner 4 for aligning an orientation flat or a notch of a substrate W in a predetermined direction. The electroless plating apparatus further includes a spin-rinse-dryer (SRD) 6 for drying a plated substrate W by rotating it at a high speed, a storage bath 14 for storing a plurality of substrate holders 42 in a vertical position, a substrate loader 10 for loading a substrate W to be plated into a substrate holder 42 and taking a plated substrate W out of a substrate holder 42, and a substrate transport robot 12 for transporting a substrate W.

A travel mechanism 5 is installed along an arrangement direction of the loading ports 2. The substrate transport robot 12 is installed on the travel mechanism 5. The aligner 4 is disposed adjacent to the travel mechanism 5. The substrate transport robot 12 moves on the travel mechanism 5 and accesses the wafer cassette set on one of the loading ports 2, takes a substrate W to be plated out of the wafer cassette, and transfers the substrate W to the substrate loader 10.

In the frame 1, there are disposed a pretreatment unit 16 for performing a pretreatment of a surface of a substrate W (e.g., removal of a copper oxide layer formed on the substrate surface) and a nuclei forming unit 18 for forming e.g., palladium nuclei on the surface of the substrate W. The pretreatment unit 16 includes a pretreatment bath 16 a for storing a pretreatment solution for pretreating the surface of the substrate W, and a rinsing bath 16 b for rinsing the substrate W, which has been immersed in the pretreatment solution, with a rinsing liquid (e.g., pure water). The nuclei forming unit 18 includes a nuclei forming bath 18 a for forming palladium nuclei on the surface of the substrate W, and a rinsing bath 18 b for rinsing the substrate W, on which palladium nuclei have been formed, with a rinsing liquid (e.g., pure water).

The electroless plating apparatus further includes a first plating unit (or a first processing unit) 20 for forming e.g., a cobalt (Co) layer on the surface of the substrate W by electroless plating, and a second plating unit (or a second processing unit) 24 for forming e.g., a gold (Au) layer on the surface of the substrate W by electroless plating. The first plating unit 20 includes a first plating bath (or a first processing bath) 20 a for storing a plating solution (or a first processing liquid), such as a cobalt plating solution, and a rinsing bath 20 b for rinsing the substrate W, which has been immersed in the plating solution in the first plating bath 20 a, with a rinsing liquid (e.g., pure water).

The second plating unit 24 includes a second plating bath (or a second processing bath) 24 a for storing a plating solution (or a second processing liquid), such as a gold plating solution, and a rinsing bath 24 b for rinsing the substrate W, which has been immersed in the plating solution in the second plating bath 24 a, with a rinsing liquid (e.g., pure water). The pretreatment unit 16, the nuclei forming unit 18, the first plating unit 20, the second plating unit 24, and the storage bath 14 are arranged in series in this order.

The first plating unit 20 and the second plating unit 24 each includes an overflow bath (not shown). The plating solution that has overflown the plating bath 20 a or 24 a flows into the overflow bath, and is returned through a circulation line (not shown) to the plating bath 20 a or 24 a. Each circulation line is provided with a filter and a plating solution temperature regulator.

The substrate loader 10 is disposed adjacent to the storage bath 14. The substrate loader 10 includes a table 26 on which a substrate holder 42 is placed in a horizontal position, and a substrate-holder tilting mechanism 28 for standing and leaning the substrate holder 42. The substrate-holder tilting mechanism 28 is provided beside the table 26. The substrate-holder tilting mechanism 28 is configured to change the substrate holder 42 from a vertical position to a horizontal position and place the substrate holder 42 on the table 26. A substrate W is loaded into and removed from the substrate holder 42 on the table 26.

The electroless plating apparatus further includes a transporter 30 for transporting a substrate W in a horizontal direction. The transporter 30 includes a fixed base 40 extending horizontally from a position beside the substrate loader 10 to a position beside the pretreatment unit 16, an arm 32 configured to be movable horizontally on the fixed base 40, and a gripper 34 mounted to the arm 32. A linear motor or a rack and pinion may be used as a driving device for horizontally moving the arm 32. The gripper 34 is configured to grip the substrate holder 42.

The substrate holder 42 will now be described with reference to FIG. 2. FIG. 2 is a diagram showing the substrate holder 42. As shown in FIG. 2, the substrate holder 42 has out portions 46, 46. A support arm 45 extends between the projecting portions 46, 46. Two holding arms 44, 44 for gripping a substrate W are secured to the support arm 45. The transporter 30 transports the substrate holder 42 with the gripper 34 gripping the support arm 45.

Each holding arm 44 has a first slit 44 a, a second slit 44 b, and a third slit 44 c. FIG. 3 shows a substrate W which is held in the slits 44 a to 44 c of each holding arm 44. Only one of the holding arms 44 is shown in FIG. 3. As shown in FIG. 3, the substrate W is held by the substrate holder 42 with the periphery of the substrate W inserted into the slits 44 a to 44 c. As shown in FIG. 2, the substrate W is slid from a position shown by a dotted line to a position shown by a solid line, so that the periphery of the substrate W is inserted into the slits 44 a to 44 c of the two holding arms 44, 44. The loading of the substrate W into the substrate holder 42 is performed by the substrate transport robot 12 shown in FIG. 1 or a substrate slide mechanism (not shown) provided on the table 26. The second slits 44 b may be omitted.

The electroless plating apparatus includes a substrate-holder advancing mechanism 50 for advancing the substrate holder 42 from a holder put-in position “IN” to a holder takeout position “OUT” while keeping a substrate W immersed in a plating solution in the first plating bath 20 a, and a substrate-holder advancing mechanism 51 for advancing the substrate holder 42 from a holder put-in position “IN” to a holder takeout position “OUT” while keeping the substrate W immersed in a plating solution in the second plating bath 24 a. The holder put-in position “IN” refers to a position where the substrate holder 42, holding a substrate W, is put in the plating bath 20 a or 20 b. The holder takeout position “OUT” refers to a position where the substrate holder 42, holding a substrate W, is taken out of the plating bath 20 a or 20 b. The substrate-holder advancing mechanisms 50, 51 have the same construction, and therefore the following description is solely given of the substrate-holder advancing mechanism 50 and a description of the substrate-holder advancing mechanism 51 will be omitted.

FIG. 4 is a perspective view of the first plating bath 20 a and the substrate-holder advancing mechanism 50. The first plating bath 20 a may be hereinafter referred to simply as plating bath 20 a. As shown in FIG. 4, the substrate-holder advancing mechanism 50 is disposed adjacent to the plating bath 20 a. The substrate-holder advancing mechanism 50 is configured to move the substrate holder 42 from the holder put-in position “IN” to the holder takeout position “OUT” in a direction indicated by arrow while keeping a substrate W immersed in the plating solution held in the first plating bath 20 a.

The substrate-holder advancing mechanism 50 includes two fixed supports 59 for supporting a plurality of substrate holders 42 and suspending the substrate holders 42 in the plating bath 20 a, two movable supports 52 for supporting the substrate holders 42, and two first actuators 53 for moving up and down (or elevating and lowering) the two movable supports 52, respectively. The two movable supports 52 are disposed adjacent to the two fixed supports 59, respectively. The fixed supports 59 and the movable supports 52 are configured to support different regions of the projecting portions 46 of the substrate holder 42.

The fixed supports 59 are disposed at both sides of the plating bath 20 a. The fixed supports 59 may be secured to both side walls of the plating bath 20 a. A plurality of recesses 59 a each for supporting the projecting portions 46 of the substrate holder 42 are formed in upper surfaces of the fixed supports 59. The recesses 59 a of each fixed support 59 are arranged in series along a direction in which the substrate holders 42 are advanced or transported in the plating bath 20 a. The substrate-holder advancing mechanism 50 is disposed between lifters 55, 56 and the plating bath 20 a. A plurality of recesses 52 a each for supporting the projecting portions 46 of the substrate holder 42 are formed in upper surfaces of the movable supports 52. The recesses 52 a of each movable support 52 are arranged in series along a direction in which the substrate holders 42 are advanced or transported in the plating bath 20 a. The first actuators 53 are coupled to the bottoms of the movable supports 52, respectively. An air cylinder, for example, may be used as each of the first actuators 53.

The substrate-holder advancing mechanism 50 further includes actuator stands 76 on which the first actuators 53 are fixed, and second actuators 75 for horizontally moving the movable supports 52 and the first actuators 53. Each second actuator 75 is coupled to each first actuator 53 via each actuator stand 76. A linear motor or a combination of a servo motor and a ball screw mechanism, for example, may be used as each second actuator 75.

The fixed supports 59 and the movable supports 52 are disposed parallel to each other. The positions of the fixed supports 59 are fixed. The movable supports 52 can be moved up and down by the first actuators 53, and can be moved horizontally by the second actuators 75. The second actuators 75 extend parallel to the fixed supports 59 so that the second actuators 75 can move the movable supports 52 in a direction parallel to the fixed supports 59. Thus, the movable supports 52, the first actuators 53, and the actuator stands 76 are horizontally moved together by the second actuators 75.

The operation of the substrate-holder advancing mechanism 50 will now be described with reference to FIG. 5. In step 1, the substrate holder 42 is placed on the fixed supports 59 by the lifter 55 shown in FIG. 1. The projecting portions 46 of the substrate holder 42 are fitted into the recesses 59 a of the fixed supports 59, so that the substrate holder 42 is suspended in the plating bath 20 a. The substrate holder 42 is now in the holder put-in position “IN” where the substrate holder 42, holding a substrate W, is put in the plating bath 20 a. While the substrate W is kept immersed in the plating solution, the substrate holder 42 is advanced from the holder put-in position “IN” to the holder takeout position “OUT” by the substrate-holder advancing mechanism 50. As described above, the holder takeout position “OUT” is a position where the substrate holder 42, holding the substrate W, is removed from the plating bath 20 a.

Next, in step 2, the first actuators 53 raise the movable supports 52 to insert the projecting portions 46 of the substrate holder 42 into the recesses 52 a of the movable supports 52. The first actuators 53 further raise the movable supports 52 together with the substrate holder 42, with its projecting portions 46 supported on the movable supports 52, thereby separating the substrate holder 42 from the fixed supports 59. In this step 2, the first actuators 53 elevate the movable supports 52 to a level higher than the fixed supports 59. The substrate holder 42 is raised by a distance such that the substrate W in its entirety, held by the substrate holder 42, is still kept immersed in the plating solution (i.e., the processing liquid) held in the plating bath 20 a.

In step 3, while the movable supports 52 are supporting the substrate holder 42 in the raised position, the second actuators 75 move the movable supports 52 and the substrate holder 42 horizontally by a predetermined distance toward the holder takeout position “OUT”. The substrate W is still kept immersed in the plating solution during this horizontal movement of the substrate holder 42. The distance of the horizontal movement of the substrate holder 42 can be set arbitrarily. In the embodiment illustrated in FIG. 5, the distance of the horizontal movement of the substrate holder 42 is equal to a distance between neighboring recesses 59 a of the fixed support 59.

In step 4, the first actuators 53 lower the movable supports 52 until the projecting portions 46 of the substrate holder 42 are supported on the fixed supports 59 and the movable supports 52 are separated from the substrate holder 42. More specifically, the first actuators 53 lower the movable supports 52 together with the substrate holder 42 to insert the projecting portions 46 of the substrate holder 42 into the recesses 59 a of the fixed supports 59, so that the substrate holder 42 is supported by the fixed supports 59 again. The first actuators 53 further lower the movable supports 52, thereby separating the movable supports 52 from the substrate holder 42. In this step 4, the first actuators 53 lower the movable supports 52 to a level lower than the fixed supports 59.

In step 5, after the movable supports 52 are separated from the substrate holder 42, the second actuators 75 horizontally move the movable supports 52 by the above-described predetermined distance toward the holder put-in position “IN”. Accordingly, the movable supports 52 are returned to the initial position shown in “STEP 1”. In step 6, a new substrate holder 42 is transported to the holder put-in position “IN”, and the projecting portions 46 of the substrate holder 42 are fitted into the recesses 59 a of the fixed supports 59.

The first actuators 53 and the second actuators 75 repeat the operations of steps 1 to 5. Consequently, the substrate holder 42 is moved from the holder put-in position “IN” to the holder takeout position “OUT” while the substrate holder 42 is moved up and down repeatedly. After the substrate holder 42 has reached the holder takeout position “OUT”, the substrate holder 42 is taken out of the plating bath 20 a by the lifter 56.

Substrate holders 42 are successively transported into the plating bath 20 a. The substrate holders 42 are put one by one into the plating bath 20 a at the holder put-in position “IN”, and removed one by one from the plating bath 20 a at the holder takeout position “OUT”. A plurality of substrate holders 42 constantly exist in the plating bath 20 a, and substrates W, held by the substrate holders 42, are being plated in the plating solution.

As can be seen in FIG. 5, as the substrate holder 42 is moved up and down, the substrate W is also moved up and down while being kept immersed in the plating solution. Because the surface of the substrate W moves up and down relative to the plating solution, the plating solution in contact with the substrate W can be replaced with a new plating solution. Furthermore, bubbles adhering to the surface of the substrate W can be removed by the vertical movement of the substrate W. Therefore, a metal film having a uniform thickness can be formed on the surface of the substrate W.

FIG. 6A is a diagram showing the substrate holder 42 before it is raised by the first actuators 53, and FIG. 613 is a diagram showing, the substrate holder 42 after it is raised by the first actuators 53. In the step 2 illustrated in FIG. 5, the first actuators 53 raise the movable supports 52 to move the substrate holder 42 from the position shown in FIG. 6A to the position shown in FIG. 6B. As shown in FIG. 6B, the substrate W held by the substrate holder 42 in the raised position remains entirely immersed in the plating solution.

In electroless plating of the substrate W, plating of the substrate W starts when the substrate W is immersed in the plating solution and terminates when the substrate W is raised from the plating solution. In this embodiment the substrate W is kept immersed in the plating solution even when the substrate holder 42 is raised by the first actuators 53. Thus, plating of the substrate W is not interrupted.

FIG. 7 is a perspective view of the first plating bath 20 a, the substrate-holder advancing mechanism 50, the lifter 55, and the lifter 56. As shown in FIG. 7, the lifter 55 and the lifter 56 are disposed adjacent to the substrate-holder advancing mechanism 50. The lifter 55 is a unidirectional lifter configured to elevate and lower the substrate holder 42, while the lifter 56 is a bidirectional lifter configured to elevate and lower the substrate holder 42 and horizontally move the substrate holder 42.

The lifter 55 includes two holder support portions 61 for supporting the two projecting portions 46 of the substrate holder 42, and two elevators 60 for elevating and lowering the holder support portions 61 together with the substrate holder 42. The holder support portions 61 and the elevators 60 are disposed outside the substrate-holder advancing mechanism 50.

The lifter 55 is configured to move the substrate holder 42 in the vertical diction so as to transport the substrate holder 42 in the vertical direction between the transporter 30 and the substrate-holder advancing mechanism 50. More specifically, the transporter 30 grips the substrate holder 42 with the gripper 34 and transports the substrate holder 42 to the lifter 55. The elevators 60 of the lifter 55 raise the holder support portions 61 so as to allow the holder support portions 61 to receive the substrate holder 42 from the transporter 30. After the holder support portions 61 receive the substrate holder 42, the elevators 60 lower the holder support portions 61 together with the substrate holder 42 to place the substrate holder 42 on the fixed supports 59 of the substrate-holder advancing mechanism 50 and immerse the substrate W in the plating solution in the plating bath 20 a. The substrate holder 42 is placed by the lifter 55 on the fixed supports 59 at the holder put-in position “IN” shown in FIG. 5 (see “STEP 1”). The lifter 55 receives the substrate holder 42 when the holder support portions 61 are in the raised positions. After transferring the substrate holder 42 to the lifter 55, the transporter 30 can be moved for transporting another substrate holder 42 holding a substrate W being processed in another processing bath.

The lifter 56 includes two holder support portions 63 for supporting the two projecting portions 46 of the substrate holder 42, two elevators 62 for elevating and lowering the holder support portions 63 together with the substrate holder 42, and two horizontal actuators 64 for horizontally moving the holder support portions 63 and the elevators 62. The holder support portions 63, the elevators 62, and the horizontal actuators 64 are disposed outside the substrate-holder advancing mechanism 50.

The lifter 56 is configured to move the substrate holder 42 in the vertical direction so as to transport the substrate holder 42 in the vertical direction between the substrate-holder advancing mechanism 50 and the transporter 30. Further, the lifter 56 is configured to horizontally transport the substrate holder 42 between the two adjacent processing baths (i.e. the plating bath 20 a and the rinsing bath 20 b). More specifically, the holder support portions 63 are raised by the elevators 62 to receive the substrate holder 42 that is placed on the fixed supports 59. The elevators 62 further raise the holder support portions 63 together with the substrate holder 42. The holder support portions 63 of the lifter 56 receive the substrate holder 42 at the holder takeout position “OUT”. The horizontal actuators 64 horizontally move the holder support portions 63 and the substrate holder 42, which are in the raised position, to the adjacent processing bath, i.e., the rinsing bath 20 b. The lifter 56 lowers the holder support portions 63 to immerse the substrate W, held by the substrate holder 42, in the rinsing liquid in the rinsing bath 20 b, and elevates the holder support portions 63 to raise the substrate W from the rinsing liquid and transfer the substrate holder 42 to the transporter 30.

As described above, the substrate W held by the substrate holder 42 is immersed in and raised from the plating solution in the plating bath 20 a and the rising liquid in the rinsing bath 20 b by the lifters 55, 56. The transporter 30 is configured to just transfer the substrate holder 42 to the lifter 55 and receive the substrate holder 42 from the lifter 56. The operations of the lifters 55, 56 to transport the substrate holder 42 can be performed independently of the operation of the transporter 30. This can increase the overall throughput of the apparatus.

The holder support portions 61, 63 of the lifters 55, 56, the recesses 59 a of the fixed supports 59, and the recesses 52 a of the movable supports 52 are arranged so as to support different regions of the projecting portions 46 of the substrate holder 42. In particular, as shown in FIG. 2, the holder support portions 61, 63 of the lifters 55, 56 support outer regions 46 a of the projecting portions 46, the recesses 59 a of the fixed supports 59 support inner regions 46 c of the projecting portions 46, and the recesses 52 a of the movable supports 52 support intermediate regions 46 b each lying between the outer region 46 a and the inner region 46 c.

The operation of the electroless plating apparatus will now be described with reference to FIG. 1. First, the substrate holder 42 in a vertical position is taken out of the storage bath 14 by a lifter 80 disposed adjacent to the storage bath 14. The lifter 80 is a bidirectional lifter configured to elevate and lower the substrate holder 42 and horizontally move the substrate holder 42. The lifter 80 has the same construction as the above-described lifter 56 shown in FIG. 7, and therefore a detailed description thereof is omitted. The lifter 80 can take out any substrate holder 42 from a number of substrate holders 42 arranged in the storage bath 14. The lifter 80 transfers the substrate holder 42 to the transporter 30, and the transporter 30 transfers the substrate holder 42 to the substrate-holder tiling mechanism 28 of the substrate loader 10. The substrate-holder tilting mechanism 28 of the substrate loader 10 changes the substrate holder 42 from a vertical position to a horizontal position, and places the substrate holder 42 on the table 26.

The substrate transport robot 12 takes one substrate W out of the wafer cassette mounted on one of the loading ports 2, and places the substrate W on the aligner 4. The aligner 4 aligns an orientation flat or a notch in a predetermined direction. Thereafter, the substrate transport robot 12 removed the substrate W from the aligner 4, and inserts the substrate W into the substrate holder 42 on the table 26. More specifically, the substrate transport robot 12 loads the substrate W into the substrate holder 42 by sliding the substrate W from the position shown by the dotted line in FIG. 2 to the position shown by the solid line. Instead, a substrate slide mechanism (not shown) for sliding the substrate W parallel to the table 26 may be provided. In that case, the substrate transport robot 12 transfers the substrate W to the substrate slide mechanism, which then loads the substrate W into the substrate holder 42.

Next, the substrate-holder tilting mechanism 28 changes the substrate holder 42 from the horizontal position to the vertical position. The gripper 34 of the arm 32 grips the substrate holder 42 in the upright position, and the transporter 30 moves the substrate holder 42 to a predetermined position above the pretreatment bath 16 a. A lifter 81 is provided adjacent to the pretreatment bath 16 a. The lifter 81 is a bidirectional lifter configured to elevate and lower the substrate holder 42 and horizontally move the substrate holder 42. The lifter 81 has the same construction as the above-described lifter 56 shown in FIG. 7, and therefore a detailed description thereof is omitted.

The lifter 81 receives the substrate holder 42 from the transporter 30, and lowers the substrate holder 42 to immerse the substrate W, held by the substrate holder 42, in a pretreatment solution in the pretreatment bath 16 a. The surface of the substrate W is pretreated with the pretreatment solution. This pretreatment is, for example, a process of removing a copper oxide layer formed on the surface of the substrate W. After the pretreatment, the lifter 81 elevates the substrate holder 42 to raise the substrate W from the pretreatment solution.

The lifter 81 horizontally moves the substrate holder 42 to the rinsing bath 16 b adjacent to the pretreatment bath 16 a, and lowers the substrate holder 42 to immerse the substrate W in a rinsing liquid in the rinsing bath 16 b. The substrate W is rinsed with the rinsing liquid. After the rinsing, the lifter 81 elevates the substrate holder 42 to raise the substrate W from the rinsing liquid in the rinsing bath 16 b.

The transporter 30 receives the substrate holder 42 from the lifter 81, and moves the substrate holder 42 to a predetermined position above the nuclei forming bath 18 a. A lifter 82 is provided adjacent to the nuclei forming bath 18 a. The lifter 82 is a bidirectional lifter configured to elevate and lower the substrate holder 42 and horizontally move the substrate holder 42. The litter 82 has the same construction as the above-described lifter 56 shown in FIG. 7, and therefore a detailed description thereof is omitted.

The lifter 82 receives the substrate holder 42 from the transporter 30, and lowers the substrate holder 42 to place the substrate W, held by the substrate holder 42, in the nuclei forming bath 18 a. In the nuclei forming bath 18 a, nuclei (e.g., palladium nuclei) necessary for deposition of a metal film are formed on the surface of the substrate W. Thereafter, the lifter 82 elevates the substrate holder 42 to raise the substrate W from the nuclei forming bath 18 a. The lifter 82 then horizontally moves the substrate holder 42 to the rinsing bath 18 b adjacent to the nuclei forming bath 18 a, and lowers the substrate holder 42 to immerse the substrate W in a rinsing liquid in the rinsing bath 18 b. The substrate W is rinsed with the rinsing liquid. After the rinsing, the lifter 82 elevates the substrate holder 42 to raise the substrate W from the rinsing liquid in the rinsing bath 18 b.

The transporter 30 receives the substrate holder 42 from the lifter 82, and moves the substrate holder 42 to a predetermined position above the plating bath 20 a. The lifter 55 receives the substrate holder 42 from the transporter 30, and lowers the substrate holder 42 to place it on the substrate-holder advancing mechanism 50 in the above-described manner. The substrate holder 42 is placed in the above-described holder put-in position “IN”. As illustrated in FIG. 5, the substrate-holder advancing mechanism 50 advances the substrate holder 42 from the holder put-in position “IN” to the holder takeout position “OUT” while keeping the substrate W in its entirety immersed in the plating solution held in the plating bath 20 a and moving up and down the substrate holder 42 repeatedly. While the substrate W thus moves in the plating solution, first-step electroless plating is performed on the surface of the substrate W. The first-step electroless plating is, for example, cobalt (Co) plating.

After a predetermined time has elapsed since the substrate W was immersed in the plating solution, a subsequent substrate holder 42 holding another substrate is put in the plating bath 20 a at the holder put-in position “IN”. Thus, substrate holders 42 are successively put in the plating bath 20 a at predetermined time intervals, and successively removed from the plating bath 20 a at the predetermined time intervals.

The lifter 56 elevates the substrate holder 42 that has reached the holder takeout position “OUT” to raise the substrate W from the plating solution. The lifter 56 then horizontally moves the substrate holder 42 to the rinsing bath 20 b adjacent to the plating bath 20 a, and lowers the substrate holder 42 to immerse the substrate W in a rinsing liquid in the rinsing bath 20 b. The substrate W is rinsed with the rinsing liquid. After the rinsing, the lifter 56 elevates the substrate holder 42 to raise the substrate W from the rinsing liquid in the rinsing bath 20 b.

The transporter 30 receives the substrate holder 42 from the lifter 56, and horizontally moves the substrate holder 42 to a predetermined position above the second plating bath 24 a. A lifter 83, a lifter 84, and the substrate-holder advancing mechanism 51 are provided adjacent to the plating bath 24 a. The lifter 83 is a unidirectional lifter configured to elevate and lower the substrate holder 42, while the lifter 84 is a bidirectional lifter configured to elevate and lower the substrate holder 42 and horizontally move the substrate holder 42. The lifter 83 and the lifter 84 have the same constructions as the above-described lifter 55 and lifter 56, respectively.

The lifter 83 receives the substrate holder 42 from the transporter 30, and lowers the substrate holder 42 to place it on the substrate-holder advancing mechanism 51. The substrate holder 42 is placed at the above-described holder put-in position “IN”. As with the substrate-holder advancing mechanism 50, the substrate-holder advancing mechanism 51 advances the substrate holder 42 from the holder put-in position “IN” to the holder takeout position “OUT” while keeping the substrate W in its entirety immersed in the plating solution in the plating bath 24 a and moving up and down the substrate holder 42 repeatedly. While the substrate W thus moves in the plating solution, second-step electroless plating is performed on the surface of the substrate W. The second-step electroless plating is, for example, gold (Au) plating.

After a predetermined time has elapsed since the substrate W was immersed in the plating solution, a subsequent substrate holder 42 holding another substrate is put in the plating bath 24 a at the holder put-in position “IN”. Thus, substrate holders 42 are successively put in the plating bath 24 a at predetermined time intervals, and successively taken out of the plating bath 24 a at the predetermined time intervals.

The lifter 84 elevates the substrate holder 42 that has reached the holder takeout position “OUT” to raise the substrate W from the plating solution. The lifter 84 then horizontally moves the substrate holder 42 to the rinsing bath 24 b adjacent to the plating bath 24 a, and lowers the substrate holder 42 to immerse the substrate W in a rinsing liquid in the rinsing bath 24 b. The substrate W is rinsed with the rinsing liquid. After the rinsing, the lifter 84 elevates the substrate holder 42 to raise the substrate W from the rinsing liquid in the rinsing bath 24 b.

The transporter 30 receives the substrate holder 42 from the lifter 84, horizontally moves the substrate holder 42, and transfers the substrate holder 42 to the substrate-holder tilting mechanism 28. The substrate-holder tilting mechanism 28 changes the substrate holder 42 from the vertical position to the horizontal position, and places the substrate holder 42 on the table 26. The substrate transport robot 12 removes the substrate W from the substrate holder 42 by sliding the substrate W from the position shown by the solid line in FIG. 2 to the position shown by the dotted line. Instead, it is possible to slide the substrate W from the solid-line position in the substrate holder 42 by means of a substrate slide mechanism (not shown) provided in the table 26, and then take the substrate W out of the substrate slide mechanism by means of the substrate transport robot 12.

Thereafter, the substrate transport robot 12 transports the substrate W to the spin-rinse-dryer 6. The spin-rinse-dryer 6 dries the substrate W by rotating it at a high speed. The substrate transport robot 12 removes the dried substrate W from the spin-rinse-dryer 6 and returns it to the wafer cassette on the loading port 2, thereby completing the sequence of processing steps for the substrate W.

Other embodiments will now be described with reference to the drawings. 9 is a schematic plan view of en electroless plating apparatus according to another embodiment. As shown in FIG. 9, the plating apparatus includes a frame 201, loading ports 202 on which wafer cassettes, each housing substrates W (e.g., as wafers) therein, are placed, a controller 203 for controlling operation of the plating apparatus, and an aligner 204 for aligning an orientation flat or a notch of a substrate W in a predetermined direction. The plating apparatus further includes a spin-rinse-dryer (SRD) 206 for drying a plated substrate W by rotating it at a high speed, substrate loaders 210 each for loading a substrate W to be plated into a substrate holder 242 (which will be described later) and removing a plated substrate W from the substrate holder 242, and a substrate transport robot 212 for transporting a substrate W.

A travel mechanism 205 is installed along an arrangement direction of the loading ports 202. The substrate transport robot 212 is installed on the travel mechanism 205. The substrate transport robot 212 moves on the travel mechanism 205 and accesses the wafer cassette set on one of the loading ports 202, takes a substrate W to be plated out of the wafer cassette, and transfers the substrate W to the substrate holder 242 in one of the substrate loaders 210. The aligner 204, the spin-rinse-dryer 206, the substrate loaders 210, and the substrate transport robot 212 are disposed in the frame 201.

In the frame 201, there are disposed a plurality of processing baths 229 for performing plating and associated processing of a substrate W, and a transporter (or a substrate holder transporter) 230 for transporting a substrate W. The transporter 230 has an arm 232 provided with a gripper 234. The transporter 230 is configured to be capable of transporting the substrate holder 242, holding a substrate W, between one of the substrate loaders 210 and the processing baths 229, and vertically moving the substrate holder 242 together with the substrate W.

The processing baths 229 are arranged in series, and the transporter 230 is disposed along an arrangement direction of the processing baths 229. The processing baths 229 and the transporter 230 constitute a plating section 231. The plating apparatus according to this embodiment includes two plating sections 231, 231 disposed in parallel. The plating sections 231, 231 are electroless plating sections for plating a surface of a substrate W with metal without passing an electric current through a plating solution. However, the plating sections 231, 231 may be electroplating sections for plating a surface of a substrate W with metal by passing an electric current through a plating solution.

The processing baths 229 of each plating section 231 include a storage bath 214 for storing substrate holders 242, a pretreatment bath 260 for pretreating a substrate W with a pretreatment solution, a rinsing bath 262 for rinsing the substrate W with a processing liquid (pure water) after the pretreatment of the substrate W, a nuclei forming bath 264 for forming e.g., palladium nuclei on the surface of the substrate W, and a rinsing bath 266 for rinsing the substrate W, which has been immersed in the processing liquid in the nuclei forming bath 264, with a processing liquid (pure water). The processing baths 229 further include a first plating bath 26 g for forming e.g., a cobalt (Co) layer or a nickel (Ni) layer on the surface of the substrate W by electroless plating, a rinsing bath 270 for rinsing the substrate W, which has been immersed in a plating solution in the first plating bath 268, with a processing liquid (pure water), a second plating bath 272 for forming e.g., a gold (Au) layer on the surface of the substrate W by electroless plating, a rinsing bath 274 for rinsing the substrate W, which has been immersed in a plating solution in the second plating bath 272, with a processing liquid (pure water), and a blow bath 275 for drying the rinsed substrate W. The first plating bath 268 is constituted by a plurality of plating cells 268 a. The pretreatment bath 260, the rinsing bath 262, the nuclei forming bath 264, the rinsing bath 266, the first plating bath 268, the rinsing bath 270, the second plating bath 272, the rinsing bath 274, the blow bath 275 and the storage bath 214 are arranged in series in this order.

The pretreatment bath 260, the nuclei forming bath 264, the first plating bath 268, the second plating bath 272, and the rinsing baths 262, 266, 270, 274 are each a processing bath having a rectangular cross-sectional shape, capable of holding a processing liquid and provided with an overflow bath (not shown). The processing liquid that has overflown each processing bath circulates through a circulation line by means of a pump and resupplied to the processing bath. Each circulation line is provided with a filter and a processing solution temperature regulator.

Two chemical supply units 290, 290 for supplying liquid chemicals, including a plating solution, necessary for plating or associated processing of a substrate W, are disposed adjacent to ends of the plating sections 231, 231. A substrate transfer section 302 is disposed adjacent to the other ends of the plating sections 231, 231. The substrate transfer section 302 includes two substrate loaders 210, 210, two spin-rinse-dryers 206, one aligner 204, one travel mechanism 205 and one substrate transport robot 212. The two spin-rinse-dryers 206 are stacked on top of each other, and therefore one spin-rinse-dryer 206 is shown in FIG. 9.

The substrate loaders 210 are disposed adjacent to the storage baths 214. Each substrate loader 210 includes a table 280 on which a substrate holder 242 is placed in a horizontal position, and a substrate-holder tilting mechanism 282 for standing and leaning the substrate holder 242. The substrate-holder tilting mechanism 282 is provided beside the table 280. The substrate-holder tilting mechanism 282 is configured to change the substrate holder 242 from a vertical position to a horizontal position and place the substrate holder 242 on the table 280.

The travel mechanism 205 is installed between the loading ports 202 and the spin-rinse-dryers 206 along the arrangement direction of the loading ports 202. The substrate transport robot 212 is installed on the travel mechanism 205. The aligner 204 is disposed adjacent to the travel mechanism 205.

Each transporter 230 includes a fixed base 240 secured to the frame 201 and extending horizontally from a position beside the substrate loader 210 to a position beside the pretreatment bath 260, a lifter 233 configured to be horizontally movable on the fixed base 240, and an arm 232 coupled to the lifter 233. The arm 232 and the lifter 233 horizontally move together, and the arm 232 is elevated and lowered by the lifter 233. A linear motor or a rack and pinion may be used as a driving device for horizontally moving the lifter 233 and the arm 232. The arm 232 has a gripper 234 which is configured to grip one substrate holder 242.

The substrate holder 242 will now be described with reference to FIG. 10, FIG. 10 is a diagram showing the substrate holder 241. As shown in FIG. 10, the substrate holder 242 includes holding arms 241, 244 for gripping a substrate W, and a support member 246 for supporting the holding arms 244, 244. Each holding arm 24 has a first slit 244 a, a second slit 244 b, and a third slit 244 c. FIG. 11 shows a substrate W which is held in the slits 244 a to 244 c of each holding arm 244. Only one of the holding arms 244 is shown in FIG. 11. As shown in FIG. 11, the substrate W is held by the substrate holder 242 with a periphery of the substrate W inserted into the slits 244 a to 244 c. As shown in FIG. 10, the periphery of the substrate W is inserted into the slits 244 a to 244 c of the two holding arms 244, 244 by sliding the substrate W from a position shown by a dotted line to a position shown by a solid line by the substrate transport robot 212 or a substrate slide mechanism (not shown) provided on the table 280.

The layout of the electroless plating apparatus according to this embodiment in the frame 201 will now be described with reference to FIG. 9. As shown in FIG. 9, the electroless plating apparatus according to this embodiment includes two plating sections (electroless plating sections) 231, 231 which are disposed in parallel with a distance from each other in the frame 201. A maintenance space 300, from which an operator can access any component of the plating apparatus, is provided between the plating sections 231, 231. The shaded area in FIG. 9 represents the maintenance space 300. The maintenance space 300 extends parallel to the transporters 230, 230 and are disposed adjacent to the transporters 230, 230, so that an operator can easily reach the transporters 230, 230 and can easily perform maintenance work on the transporters 230, 230. Part of the maintenance space 300 lies between the chemical supply units 290, 290.

The plating sections 231, 231 are disposed on both sides of the maintenance space 300 so that an operator can quickly view both of the plating sections 231, 231 from the maintenance space 300. Further, the plating apparatus having the two plating sections 231, 231 can be operated with various plating conditions. For example, it is possible to stop the operation of one plating section 231 and perform maintenance work on the plating section 231, while operating the other plating section 231. Further, it is possible to use different processing liquids and perform different plating processes in the plating sections 231, 231.

The spin-rinse-dryer 206 is disposed between the substrate loaders 210, 210 and adjacent to the end of the maintenance space 300, so that an operator can easily access the spin-rinse-dryer 206 and can easily perform maintenance work on the spin-rinse-dryer 206.

FIG. 12 is a diagram showing the electroless plating apparatus of FIG. 9 as viewed in the direction of arrow A. As shown in FIG. 12, filters 304 which do not permit passage of unwanted matter contained in a processing liquid and filter boxes 305 for housing the filters 304 therein are disposed on an upper area of the exterior wall of the frame 201. It is common practice in conventional plating apparatuses to dispose the filters 304 on a lower area of the exterior wall of the frame 201. This requires considerable effort for work to repair or replace the filters 304. In contrast, because the filters 304 are disposed on an upper area of the exterior wall of the frame 201 in the plating apparatus according to this embodiment, an operator can easily reach the filters 304. This enables the operator to easily perform maintenance work (such as repair or replacement) on the filters 304.

FIG. 13 is a schematic cross-sectional view taken along line B-B of FIG. 9. In FIG. 13, the chemical supply units 290 are shown schematically for a better understanding of the drawing. As shown in FIG. 13, a platform 300 a as a foothold for an operator and support legs 300 b, 300 b for supporting the platform 300 a are provided between the plating sections 231, 231. The maintenance space 300 is formed over the platform 300 a, while a piping space 306 is formed under the platform 300 a. Pipes for conveying processing liquids for use in plating or associated processing are concentrated in the piping space 306. The pipes are coupled e.g., to the filters 304 and/or the chemical supply units 290, 290.

Utility fluid introduction ports (or joints) 308 for receiving a utility fluid (e.g., pure water or nitrogen gas), which is necessary for the operation of the electroless plating apparatus, from a utility supply facility and for supplying the fluid to the plating sections 231, 231 may be provided under the platform 300 a (in the piping space 306). The utility fluid may be supplied through a pipe from below the floor on which the plating apparatus is installed, as shown in FIG. 13.

According to this embodiment, an operator can easily view the interior of each of the processing baths 229 from the maintenance space 300 provided between the plating sections 231, 231. Because the filters 304 and the filter boxes 305 are disposed on the upper area of the exterior wall of the plating apparatus, replacement of the filters 304 can be performed from the outside of the plating apparatus. Because the filter boxes 305 are provided on the upper area of the exterior wall of the plating apparatus, a certain limitation is placed on maintenance work on the interior of the plating apparatus when the maintenance work is performed from the outside of the apparatus. However, since the maintenance space 300 is provided, an operator can perform easy maintenance work on the interior of the plating apparatus. In addition, providing the piping space 306 under the maintenance space 300 can improve efficient use of the space.

The operation of the plating apparatus having the above construction will now be described. First, the substrate holder 242 in a vertical position is taken from one of the storage baths 214 by the arm 232 of the transporter 230. The arm 232 holding the substrate holder 242 moves horizontally and transfers the substrate holder 242 to the substrate loader 210. The substrate-holder tilting mechanism 282 of the substrate loader 210 changes the substrate holder 242 from the vertical position to the horizontal position, and places the substrate holder 242 on the table 280.

The substrate transport robot 212 takes one substrate W from the cassette mounted on one of the loading ports 202, and places the substrate W on the aligner 204. The aligner 204 aligns an orientation flat or a notch in a predetermined direction. Thereafter, the substrate transport robot 212 removes the substrate W from the aligner 204, and inserts the substrate W into the substrate holder 242 on the table 280. More specifically, the substrate transport robot 212 horizontally moves the substrate W to a predetermined position, and loads the substrate W into the substrate holder 242 by sliding the substrate W from the position shown by the dotted line in FIG. 10 to the position shown by the solid line so as to insert the substrate W into the slits 244 a to 244 c. Instead, a substrate slide mechanism (not shown) for sliding the substrate W parallel to the table 280 may be provided. In that case, the substrate transport robot 212 transfers the substrate W to the substrate slide mechanism, which loads the substrate W into the substrate holder 242.

Next, the substrate-holder tilting mechanism 282 changes the substrate holder 242 from the horizontal position to the vertical position. The gripper 234 of the arm 232 grips the substrate holder 242 in the upright position, and the transporter 230 horizontally moves the substrate W and the substrate holder 242 to a predetermined position above the pretreatment bath 260. The lifter 233 lowers the atm 232 to immerse the substrate W and the substrate holder 242 in a processing liquid in the pretreatment bath 260, thereby cleaning the surface of the substrate W. After the pretreatment of the substrate W, the lifter 233 elevates the arm 232 to raise the substrate W and the substrate holder 242 from the processing liquid in the pretreatment bath 260.

Next, the arm 232 moves the substrate holder 242 to a predetermined position above the rinsing bath 262. The lifter 233 lowers the arm 232 to immerse the substrate W and the substrate holder 242 in a processing liquid (typically pure water) in the rinsing bath 262, thereby rinsing the surfaces of the substrate W and the substrate holder 242. After the rinsing of the substrate W, the lifter 233 elevates the arm 232 to raise the substrate W and the substrate holder 242 from the processing liquid in the rinsing bath 262.

Next, the arm 232 moves the substrate holder 242 to a predetermined position above the nuclei forming bath 264. The lifter 233 lowers the arm 232 to immerse the substrate W and the substrate holder 242 in a processing liquid in the nuclei forming bath 264, thereby forming e.g., palladium nuclei (palladium catalyst) on the surface of the substrate W. Thereafter, the lifter 233 elevates the arm 232 to raise the substrate W and the substrate holder 242 from the processing liquid in the nuclei forming bath 264.

Next, the arm 232 moves the substrate holder 242 to a predetermined position above the rinsing bath 266. The lifter 233 lowers the arm 232 to immerse the substrate W and the substrate holder 242 in a processing liquid (typically pure water) in the rinsing bath 266, thereby rinsing the surfaces of the substrate W and the substrate holder 242. Thereafter, the lifter 233 elevates the arm 232 to raise the substrate W and the substrate holder 242 from the processing liquid in the rinsing bath 266.

Next, the arm 232 moves the substrate holder 242 to a predetermined position above the first plating bath 268. The lifter 233 lowers the arm 232 to immerse the substrate W and the substrate holder 242 in a plating solution (processing liquid) held in one of the plating cells 268 a of the first plating bath 268, thereby electroless-plating the surface of the substrate V e.g., with cobalt (Co) or nickel (Ni). The same operation is repeated for a plurality of substrates W to immerse the substrates W in the plating solution (processing liquid) in all the plating cells 268 a. After the elapse of a predetermined plating time the transporter 230 raises substrate holders 242, holding the substrates W, one by one from the plating solution in the first plating bath 268.

Next, the arm 232 of the transporter 230 moves the substrate holder 242 to a predetermined position above the rinsing bath 270. The lifter 233 lowers the arm 232 to immerse the substrate W and the substrate holder 242 in a processing liquid (typically pure water) in the rinsing bath 270, thereby rinsing the surfaces of the substrate W and the substrate holder 242. Thereafter, the lifter 233 elevates the arm 232 to raise the substrate W and the substrate holder 242 from the processing liquid in the rinsing bath 270.

Next, the arm 232 moves the substrate holder 242 to a predetermined position above the second plating bath 272. The lifter 233 lowers the arm 232 to immerse the substrate W and the substrate holder 242 in a plating solution (processing liquid) in the second plating bath 272, thereby forming a gold (Au) layer on the peace of the substrate W by electroless plating. Thereafter, the lifter 233 elevates the arm 232 to raise the substrate W and the substrate holder 242 from the plating solution in the second plating bath 272.

Next, the arm 232 moves the substrate W and the substrate holder 242 to a predetermined position above the rinsing bath 274. The lifter 233 lowers the arm 232 to immerse the substrate W and the substrate holder 242 in a processing liquid (typically pure water) in the rinsing bath 274, thereby rinsing the surface of the substrate W. Thereafter, the lifter 233 elevates the arm 232 to raise the substrate W and the substrate holder 242 from the processing liquid in the rinsing bath 274.

After the plating of the substrate W, the arm 232 horizontally moves the substrate W and the substrate holder 242 to a position above the blow bath 275. The lifter 233 lowers the arm 232 to set the substrate W and the substrate holder 242 at a predetermined position in the blow bath 275. The blow bath 275 generates flow of air or an inert gas (e.g., N₂) blowing onto the surfaces of the substrate holder 242 and the substrate W held by the substrate holder 242 to remove liquid droplets from the substrate holder 242 and the substrate W, thereby drying the substrate holder 242 and the substrate W. After completion of the gas blowing, the gripper 234 of the arm 232 grips the substrate holder 242, and the lifter 233 elevates the arm 232 to raise the substrate holder 242 from the blow bath 275.

The arm 232 moves horizontally and transfers the substrate holder 242 to the substrate-holder tilting mechanism 282. The substrate-holder tilting mechanism 28 turns the substrate holder 282 from the vertical position to the horizontal position, and places the substrate holder 242 on the table 280. The substrate transport robot 212 removes the substrate W from the substrate holder 242 by sliding the substrate W from the position shown by the solid line in FIG. 10 to the position shown by the dotted line. Instead, it is possible to slide the substrate W from the solid-line position in the substrate holder 242 by means of a substrate slide mechanism (not shown) provided in the table 280, and then take the substrate W out of the substrate slide mechanism by means of the substrate transport robot 212. Thereafter, the substrate transport robot 212 transports the substrate W to the spin-rinse-dryer 206. The spin-rinse-dryer 206 dries the substrate W by rotating it at a high speed. The substrate transport robot 212 removes the dried substrate W from the spin-rinse-dryer 206 and returns it to the cassette on the loading port 202, thereby completing the sequence of processing steps for the one substrate.

FIG. 14 is a schematic plan view of an electroless plating apparatus according to yet another embodiment. The processing baths 229 of this embodiment are the same as the processing baths 229 of the preceding embodiment shown in FIG. 9, and are therefore illustrated in a simplified manner in FIG. 14. The shaded area in FIG. 14 represents a maintenance space 300. The plating apparatus shown in FIG. 14 differs from the plating apparatus shown in FIG. 9 in that the spin-rinse-dryers 206 (one of which is shown in FIG. 14) and the substrate loaders 210, 210 are disposed adjacent to the maintenance space 300. Owing to such a layout according to this embodiment, an operator can easily access the spin-rinse-dryers 206 and the substrate loaders 210, 210 and easily perform maintenance work on them. In this embodiment the transporters 230, 230 of the plating sections 231, 231 are not disposed adjacent to the maintenance space 300. However, it is possible to dispose the transporters 230, 230 adjacent to the maintenance space 300 as shown in FIG. 9.

In the above-described two embodiments, the lifter 233 of each transporter 230 horizontally and vertically moves the substrate holder 242. Instead, it is possible to provide lifters separately from the transporters 230. In that case, a plurality of lifters are provided adjacent to each processing bath 229, and each transporter 230 is configured to move the arm 232 only horizontally.

While the present invention has been described with reference to preferred embodiments, it is understood that the present invention is not limited to the embodiments described above, but is capable of various changes and modifications within the scope of the inventive concept as expressed herein. For example, although in the above-described embodiments the maintenance space 300 is provided in the electroless plating apparatus, the maintenance space 300 may be provided in an electroplating apparatus. Providing the maintenance space 300 in an electroplating apparatus can also achieve the same advantageous effects as described above. 

What is claimed is:
 1. A wet processing apparatus comprising: a substrate holder configured to hold a substrate; a processing bath configured to store a processing liquid therein; and a substrate-holder advancing mechanism configured to move the substrate holder from a holder put-in position to a holder takeout position in the processing bath while keeping the substrate, held by the substrate holder, immersed in the processing liquid, wherein the substrate-holder advancing mechanism includes a fixed support configured to support the substrate holder and suspend the substrate holder in the processing bath, a movable support disposed adjacent to the fixed support and configured to support the substrate holder, and an actuator configured to elevate the movable support to raise the substrate holder until the substrate holder is separated from the fixed support, move the movable support together with the substrate holder by a predetermined distance toward the holder takeout position, lower the movable support until the substrate holder is supported on the fixed support and the movable support is separated from the substrate holder, and move the movable support by the predetermined distance toward the holder put-in position.
 2. The wet processing apparatus according to claim 1, wherein the actuator comprises a first actuator configured to elevate and lower the movable support, and a second actuator configured to horizontally move the movable support.
 3. The wet processing apparatus according to claim 1, further comprising: a transporter configured to horizontally transport the substrate holder; and a lifter configured to vertically transport the substrate holder between the transporter and the substrate-holder advancing mechanism, the lifter being configured to lower the substrate holder to immerse the substrate, held by the substrate holder, in the processing liquid in the processing bath and raise the substrate holder from the processing bath.
 4. The wet processing apparatus according to claim 1, wherein: the substrate holder has outwardly-projecting portions; and the fixed support has a plurality of recesses into which the projecting portions of the substrate holder are to be fitted.
 5. The wet processing apparatus according to claim 4, wherein the movable support has a plurality of recesses into which the projecting portions of the substrate holder are to be fitted.
 6. A plating apparatus for plating a substrate, the plating apparatus comprising: a substrate holder configured to hold the substrate; and a plurality of plating sections arranged in parallel, wherein each of the plating sections includes a plurality of processing baths used for plating of the substrate, and a substrate-holder transporter configured to transport the substrate holder, holding the substrate, between the processing baths, and wherein a maintenance space is provided between the plating sections.
 7. The plating apparatus according to claim 6, wherein the maintenance space extends parallel to the substrate-holder transporter.
 8. The plating apparatus according to claim 6, wherein a piping space in which pipes for conveying processing liquids to the processing baths are disposed is formed below the maintenance space.
 9. The plating apparatus according to claim 6, wherein a utility fluid introduction port configured to supply a utility fluid, which is necessary for operation of the plating apparatus, to the plating sections is provided below the maintenance space.
 10. The plating apparatus according to claim 6, further comprising: a substrate transfer section disposed adjacent to the maintenance space and configured to transfer the substrate to the substrate holder transporter.
 11. The plating apparatus according to claim 10, wherein the substrate transfer section includes a spin-rinse-dryer configured to dry the substrate by rotating the substrate, and the spin-rinse-dryer is disposed adjacent to the maintenance space.
 12. The plating apparatus according to claim 6, wherein the plating sections are electroless plating sections.
 13. The plating apparatus according to claim 6, wherein the plating sections are electroplating sections. 